Performance Characteristics of the McMaster Positron Emission Tomograph

The McMaster Positron Emission Tomograph is an instrument designed for the high resolution cross sectional study of the human brain. The detector head comprises 160 Bismuth Germanate crystals, each coupled to a 12.7 mm photomultiplier tube, closely packed on a ring, 53.5 cm in diameter. The performance characteristics of the tomograph have been measured. The spatial resolution is 8 mm (FWHM) in the stationary mode. The slice thickness is 10 mm. The resolution element is a cube of side 8 mm. The sensitivity of the tomograph was measured using a cylindrical lucite phantom, 20 cm in diameter and 20 cm long, uniformly filled with a 1 ¿Ci/ml solution of 68Ga. The total number of coincident events is 18,200 cps for a 10 mm slice. Of these, 2200 cps are random coincidences. The instrument has been in clinical use for the past 18 months.